Say that your clutch (or cable) breaks. Now you have direct drive, and you're miles from home.
To get home under power, drop your bike stand, making sure the back tire is off ground. Start engine. Release bike stand, but DON'T jump on bike. Engine will bog but still run. push bike as fast as you can.....then jump on!
When you have to stop, jump off bike and lift rear tire off ground. When time to go, drop bike and push as fast as you can. Jump on again.
This will get you home.
Ask me how I know this.